In the specs for HTML 4.0, section 3.3.4, I have found the following. Note
that it only addresses omitted value for boolean attributes. I have not
found anything for other types of attributes. I may have missed.
<quote>
Boolean attributes
Some attributes play the role of boolean variables (e.g., the selected
attribute for the OPTION element). Their appearance in the start tag of an
element implies that the value of the attribute is "true". Their absence
implies a value of "false".
Boolean attributes may legally take a single value: the name of the
attribute itself (e.g., selected="selected").
This example defines the selected attribute to be a boolean attribute.
selected (selected) #IMPLIED -- reduced inter-item spacing --
The attribute is set to "true" by appearing in the element's start tag:
<OPTION selected="selected">
...contents...
<OPTION>
In HTML, boolean attributes may be appear in minimized form -- the
attribute's value appears alone in the element's start tag. Thus, selected
may be set by writing:
<OPTION selected>
instead of:
<OPTION selected="selected">
Authors should be aware than many user agents only recognize the minimized
form of boolean attributes and not the full form.
<end of quote>
Shalom (Regards), Mati
Bidi Architect
Globalization Center Of Competency - Bidirectional Scripts
IBM Israel
Phone: +972 2 5888802 Fax: +972 2 5870333 Mobile: +972 52
2554160
From: "Aharon (Vladimir) Lanin" <aharon@google.com>
To: Tab Atkins <tabatkins@google.com>, public-i18n-bidi@w3.org
Date: 19/09/2010 16:25
Subject: HTML attribute with no value
Sent by: public-i18n-bidi-request@w3.org
In the f2f, we said:
ubi syntax is ubi=ג€